Mosquito Repellant Immune

DEET, the widely used insect repellent, is becoming less and less effective at repelling mosquitoes, according to new research done by Scientists from the London School of Hygiene and Tropical Medicine. A landmark study has found that while mosquitoes are initially repelled by the substance, they ignore it if they are later exposed to it again.

The study tested the response to DEET on Aedes Aegypti mosquitoes, which are notorious for biting during the day and are capable of transmitting dengue fever and yellow fever viruses.

Researches in the past had demonstrated how some mosquitoes were genetically immune to the substance, but the new research has shown that even those that would usually be deterred developed a resistance.

Scientists say that results underline how more research is needed to find alternatives to the chemical. Dr. James Logan, who led the research, said: ‘The more we understand about how repellents work and how mosquitoes detect them, the better we can work out ways to get around the problem when they do become resistant to repellents.’

DEET is one of the most widely used active ingredients in insect repellents. It was developed by the US military, until recently it was not clear how the chemical worked, but recent research suggests that mosquitoes simply do not like the smell.

The new study involved providing the mosquitoes with an arm treated with DEET.

As expected, they were initially put off by the substance, but surprisingly, several hours later not all the mosquitoes were deterred by the repellant.